The really slow tube leak?

Ok I am a competent mechanic change a flat right. I have this Bontrager ( no
crap please it is just a tube) 700 18-23 tube I use for my road bike on
Conti GP 4's II. I get a flat and find the hole and patch it, in fact I have
two patches on the tube. I pump in up and no leaks. I cannot hear a leak and
even the under water test shows no leak. So I put it on the bike and pump to
115 psi and then overnight it goes to 60 psi and then next day flat.
Normally I lose maybe 5-10 overnight and have pump the tire to 120 and maybe
3 days later and 60 miles of riding they go to 90 psi.

What is wrong with this one tube. I am guess it has a leak I cannot find or
for some reason the seams or they way they made this particular tube it is
not real airtight. I take some expert advice and of course I assume all
tubes butyl at least are probably similar in quality. I manage to go about
about 18 months and 8000 miles of no flats then boom, I get two in a row on
consecutive days gets me weird since I take off in pitch dark out in the
country at 5 am when it can be very cold. I take all the stuff with me but
would hate to have this happen every other day. In fact I could live with it
maybe 3-4 times a year but............I try avoid roads that have issues.

Deacon Mark Cleary
Epiphany Roman Catholic Church

On 14/11/2015 01:22, mark cleary wrote:
Ok I am a competent mechanic change a flat right. I have this Bontrager
( no crap please it is just a tube) 700 18-23 tube I use for my road
bike on Conti GP 4's II. I get a flat and find the hole and patch it, in
fact I have two patches on the tube. I pump in up and no leaks. I cannot
hear a leak and even the under water test shows no leak. So I put it on
the bike and pump to 115 psi and then overnight it goes to 60 psi and
then next day flat. Normally I lose maybe 5-10 overnight and have pump
the tire to 120 and maybe 3 days later and 60 miles of riding they go to
90 psi.

What is wrong with this one tube. I am guess it has a leak I cannot find
or for some reason the seams or they way they made this particular tube
it is not real airtight.

Try inflating it till it looks silly (the patches will form waists) and
then the underwater test (including valve). When you pump up a tube to
test it, you don't get anything like the pressure it has in the tyre.

If that gets nowhere, junk the tube and put a new one in, they're not
that expensive :-)

My slow leak problem was on a suspension fork. I'd pump it to 200psi
(tandem, needs to be on the high end), then a while later it would be
down. So I'd repump. Annoying, but I could cope.
It also had a problem leaking oil past the seals. Annoying.
One day on a ride, the seal blew, thowing oil over the brakes. Really
annoying, almost a very long walk home.
Back home I took it apart. There was the high pressure chamber, which
did the springy stuff, and the external facing chamber was at normal air
prressure. I pumped it up again, and it went down slowly. Eventually I
took it apart enough to pump the high pressure bit up and put it
underwater - where, very slowly, a little bubble appeared on the 1mm
thick aluminium. No visible defect, but it was leaking.
Which caused all the other problems - the low pressure chamber was
gradually gaining pressure from the HP leak, which forced the oil past
the seals (upside-down fork), and the blowing seal thing.
I called the manufacturer, explained the problem, they sent me a new HP
chamber, and it's worked properly ever since.

mark cleary wrote:
Ok I am a competent mechanic change a flat right. I have this Bontrager ( no
crap please it is just a tube) 700 18-23 tube I use for my road bike on
Conti GP 4's II. I get a flat and find the hole and patch it, in fact I have
two patches on the tube. I pump in up and no leaks. I cannot hear a leak and
even the under water test shows no leak. So I put it on the bike and pump to
115 psi and then overnight it goes to 60 psi and then next day flat.
Normally I lose maybe 5-10 overnight and have pump the tire to 120 and maybe
3 days later and 60 miles of riding they go to 90 psi.

What is wrong with this one tube. I am guess it has a leak I cannot find or
for some reason the seams or they way they made this particular tube it is
not real airtight. I take some expert advice and of course I assume all
tubes butyl at least are probably similar in quality. I manage to go about
about 18 months and 8000 miles of no flats then boom, I get two in a row on
consecutive days gets me weird since I take off in pitch dark out in the
country at 5 am when it can be very cold. I take all the stuff with me but
would hate to have this happen every other day. In fact I could live with it
maybe 3-4 times a year but............I try avoid roads that have issues.

Deacon Mark Cleary
Epiphany Roman Catholic Church



Not sure exactly what you're asking. Are these pinch flats? I started
getting snake bites on one wheel. Turned out to be a small slit on the
inside of the tire. Happened when I hit a pothole hard a couple weeks
before. Basically if you start flatting for no reason, check the tire.

--
duane

No it is not a pinch flat I just happen to have patched the particular tube
in two separate places. Not a tire problem I checked that for any points
that could case a hole in the tube. In fact I put the tube on another rear
wheel I use for my bike that is on the trainer and sure enough I can get a
an hour on the trainer no problem. Come back a day later and the tire was at
50 psi.



Deacon Mark Cleary
Epiphany Roman Catholic Church
"Duane" wrote in message
...

mark cleary wrote:
Ok I am a competent mechanic change a flat right. I have this Bontrager
( no
crap please it is just a tube) 700 18-23 tube I use for my road bike on
Conti GP 4's II. I get a flat and find the hole and patch it, in fact I
have
two patches on the tube. I pump in up and no leaks. I cannot hear a leak
and
even the under water test shows no leak. So I put it on the bike and pump
to
115 psi and then overnight it goes to 60 psi and then next day flat.
Normally I lose maybe 5-10 overnight and have pump the tire to 120 and
maybe
3 days later and 60 miles of riding they go to 90 psi.

What is wrong with this one tube. I am guess it has a leak I cannot find
or
for some reason the seams or they way they made this particular tube it is
not real airtight. I take some expert advice and of course I assume all
tubes butyl at least are probably similar in quality. I manage to go about
about 18 months and 8000 miles of no flats then boom, I get two in a row
on
consecutive days gets me weird since I take off in pitch dark out in the
country at 5 am when it can be very cold. I take all the stuff with me but
would hate to have this happen every other day. In fact I could live with
it
maybe 3-4 times a year but............I try avoid roads that have issues.

Deacon Mark Cleary
Epiphany Roman Catholic Church



Not sure exactly what you're asking. Are these pinch flats? I started
getting snake bites on one wheel. Turned out to be a small slit on the
inside of the tire. Happened when I hit a pothole hard a couple weeks
before. Basically if you start flatting for no reason, check the tire.

--
duane

mark cleary wrote:
No it is not a pinch flat I just happen to have patched the particular tube
in two separate places. Not a tire problem I checked that for any points
that could case a hole in the tube. In fact I put the tube on another rear
wheel I use for my bike that is on the trainer and sure enough I can get a
an hour on the trainer no problem. Come back a day later and the tire was at
50 psi.



Deacon Mark Cleary
Epiphany Roman Catholic Church
"Duane" wrote in message
...

mark cleary wrote:
Ok I am a competent mechanic change a flat right. I have this Bontrager
( no
crap please it is just a tube) 700 18-23 tube I use for my road bike on
Conti GP 4's II. I get a flat and find the hole and patch it, in fact I
have
two patches on the tube. I pump in up and no leaks. I cannot hear a leak
and
even the under water test shows no leak. So I put it on the bike and pump
to
115 psi and then overnight it goes to 60 psi and then next day flat.
Normally I lose maybe 5-10 overnight and have pump the tire to 120 and
maybe
3 days later and 60 miles of riding they go to 90 psi.

What is wrong with this one tube. I am guess it has a leak I cannot find
or
for some reason the seams or they way they made this particular tube it is
not real airtight. I take some expert advice and of course I assume all
tubes butyl at least are probably similar in quality. I manage to go about
about 18 months and 8000 miles of no flats then boom, I get two in a row
on
consecutive days gets me weird since I take off in pitch dark out in the
country at 5 am when it can be very cold. I take all the stuff with me but
would hate to have this happen every other day. In fact I could live with
it
maybe 3-4 times a year but............I try avoid roads that have issues.

Deacon Mark Cleary
Epiphany Roman Catholic Church



Not sure exactly what you're asking. Are these pinch flats? I started
getting snake bites on one wheel. Turned out to be a small slit on the
inside of the tire. Happened when I hit a pothole hard a couple weeks
before. Basically if you start flatting for no reason, check the tire.


I assume you're looking at this as a puzzle or something. 2 patches and
still slow leak? I'd recycle the tube and give it up as undependable.

--
duane

Clive George wrote:
:On 14/11/2015 01:22, mark cleary wrote:

:Try inflating it till it looks silly (the patches will form waists) and
:then the underwater test (including valve). When you pump up a tube to
:test it, you don't get anything like the pressure it has in the tyre.

:If that gets nowhere, junk the tube and put a new one in, they're not
:that expensive :-)

What he said. That's a slow leak, and they're hard to find at low
pressure. I'd probaby just toss the tube, though. It's quite likely
it's the valve, I'd bet on the valve, or the valve's attachment to
the tube.



--
There's a rather large difference between ****ing on a 600V third rail
and a 33 kV power line.

On Friday, November 13, 2015 at 8:22:40 PM UTC-5, mark cleary wrote:
Ok I am a competent mechanic change a flat right. I have this Bontrager ( no
crap please it is just a tube) 700 18-23 tube I use for my road bike on
Conti GP 4's II. I get a flat and find the hole and patch it, in fact I have
two patches on the tube. I pump in up and no leaks. I cannot hear a leak and
even the under water test shows no leak. So I put it on the bike and pump to
115 psi and then overnight it goes to 60 psi and then next day flat.
Normally I lose maybe 5-10 overnight and have pump the tire to 120 and maybe
3 days later and 60 miles of riding they go to 90 psi.

What is wrong with this one tube. I am guess it has a leak I cannot find or
for some reason the seams or they way they made this particular tube it is
not real airtight. I take some expert advice and of course I assume all
tubes butyl at least are probably similar in quality. I manage to go about
about 18 months and 8000 miles of no flats then boom, I get two in a row on
consecutive days gets me weird since I take off in pitch dark out in the
country at 5 am when it can be very cold. I take all the stuff with me but
would hate to have this happen every other day. In fact I could live with it
maybe 3-4 times a year but............I try avoid roads that have issues.

Deacon Mark Cleary
Epiphany Roman Catholic Church

I had a similar problem a few years ago. Pump up the tube and no visible leak but tube went low within a day. Then I pumped up the tube mounted on the rim with the tire and saw bubbles. Eventually junked the tube as it was tiny holes that ONLY opened when the pressure was up. Once the pressure got low enough there was no further air loss.

Cheers

On 14/11/15 02:22, mark cleary wrote:
Ok I am a competent mechanic change a flat right. I have this Bontrager
( no crap please it is just a tube) 700 18-23 tube I use for my road
bike on Conti GP 4's II. I get a flat and find the hole and patch it, in
fact I have two patches on the tube. I pump in up and no leaks. I cannot
hear a leak and even the under water test shows no leak. So I put it on
the bike and pump to 115 psi and then overnight it goes to 60 psi and
then next day flat. Normally I lose maybe 5-10 overnight and have pump
the tire to 120 and maybe 3 days later and 60 miles of riding they go to
90 psi.

What is wrong with this one tube. I am guess it has a leak I cannot find
or for some reason the seams or they way they made this particular tube
it is not real airtight. I take some expert advice and of course I
assume all tubes butyl at least are probably similar in quality. I
manage to go about about 18 months and 8000 miles of no flats then boom,
I get two in a row on consecutive days gets me weird since I take off in
pitch dark out in the country at 5 am when it can be very cold. I take
all the stuff with me but would hate to have this happen every other
day. In fact I could live with it maybe 3-4 times a year
but............I try avoid roads that have issues.

Ok, first off, tubes are cheap!

Next, there are two ways forward, one is to inflate the tube to 'Eeek!'
before the water test. I don't like doing this, it balloons a lot! Or,
when doing the water test, do the tube in 6" segments at a time, and
stretch it to about 9" while underwater, and *wait*. Should take about
5 minutes to do a tube using this method.

If no bubbles, it's the valve.

I often use a *small* amount of washing up liquid to help break trapped
air away from the surface, but I also sacrifice chickens to the puncture
Dog.

On 11/13/2015 7:22 PM, mark cleary wrote:
Ok I am a competent mechanic change a flat right. I have
this Bontrager ( no crap please it is just a tube) 700 18-23
tube I use for my road bike on Conti GP 4's II. I get a flat
and find the hole and patch it, in fact I have two patches
on the tube. I pump in up and no leaks. I cannot hear a leak
and even the under water test shows no leak. So I put it on
the bike and pump to 115 psi and then overnight it goes to
60 psi and then next day flat. Normally I lose maybe 5-10
overnight and have pump the tire to 120 and maybe 3 days
later and 60 miles of riding they go to 90 psi.

What is wrong with this one tube. I am guess it has a leak I
cannot find or for some reason the seams or they way they
made this particular tube it is not real airtight. I take
some expert advice and of course I assume all tubes butyl at
least are probably similar in quality. I manage to go about
about 18 months and 8000 miles of no flats then boom, I get
two in a row on consecutive days gets me weird since I take
off in pitch dark out in the country at 5 am when it can be
very cold. I take all the stuff with me but would hate to
have this happen every other day. In fact I could live with
it maybe 3-4 times a year but............I try avoid roads
that have issues.

Deacon Mark Cleary
Epiphany Roman Catholic Church

Yes, an annoyingly common problem. You might inflate it more
outside the tire next time, in that very small punctures
will distend with larger diameter and greater airflow,
perhaps making it more visible. Then again some resist
detection; such is life.

Do thoroughly inspect the inside of the tire in a good light
and feel for small flecks of glass or wire before installing
your new tube. I don't know of any magic.

--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971

AMuzi wrote:

o thoroughly inspect the inside of the tire in a good light
:and feel for small flecks of glass or wire before installing
:your new tube. I don't know of any magic.

I find a fluffed up cotton ball works very well for that. It'll snag
on tiny pieces of glass and such that you couldn't see.


--
sig 128